From patchwork Sat Sep 14 08:52:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 11145649 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 27AFD112B for ; Sat, 14 Sep 2019 08:55:53 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0C67B20717 for ; Sat, 14 Sep 2019 08:55:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0C67B20717 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1i93ox-0000rO-7M; Sat, 14 Sep 2019 08:54:19 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1i93ov-0000pD-VS for xen-devel@lists.xenproject.org; Sat, 14 Sep 2019 08:54:18 +0000 X-Inumbo-ID: 139e9c90-d6cd-11e9-b76c-bc764e2007e4 Received: from mx1.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 139e9c90-d6cd-11e9-b76c-bc764e2007e4; Sat, 14 Sep 2019 08:53:10 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 64B18B67F; Sat, 14 Sep 2019 08:53:09 +0000 (UTC) From: Juergen Gross To: xen-devel@lists.xenproject.org Date: Sat, 14 Sep 2019 10:52:50 +0200 Message-Id: <20190914085251.18816-47-jgross@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20190914085251.18816-1-jgross@suse.com> References: <20190914085251.18816-1-jgross@suse.com> Subject: [Xen-devel] [PATCH v3 46/47] xen/sched: disable scheduling when entering ACPI deep sleep states X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Juergen Gross , Stefano Stabellini , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , Tim Deegan , Julien Grall , Jan Beulich , Dario Faggioli , =?utf-8?q?Roger_Pau_Monn=C3=A9?= MIME-Version: 1.0 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" When entering deep sleep states all domains are paused resulting in all cpus only running idle vcpus. This enables us to stop scheduling completely in order to avoid synchronization problems with core scheduling when individual cpus are offlined. Disabling the scheduler is done by replacing the softirq handler with a dummy scheduling routine only enabling tasklets to run. Signed-off-by: Juergen Gross Acked-by: Jan Beulich Reviewed-by: Dario Faggioli --- V2: new patch --- xen/arch/x86/acpi/power.c | 4 ++++ xen/common/schedule.c | 31 +++++++++++++++++++++++++++++-- xen/include/xen/sched.h | 2 ++ 3 files changed, 35 insertions(+), 2 deletions(-) diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c index e3954eeb75..8ce70baf01 100644 --- a/xen/arch/x86/acpi/power.c +++ b/xen/arch/x86/acpi/power.c @@ -145,12 +145,16 @@ static void freeze_domains(void) for_each_domain ( d ) domain_pause(d); rcu_read_unlock(&domlist_read_lock); + + scheduler_disable(); } static void thaw_domains(void) { struct domain *d; + scheduler_enable(); + rcu_read_lock(&domlist_read_lock); for_each_domain ( d ) { diff --git a/xen/common/schedule.c b/xen/common/schedule.c index 4b2ccb7ddc..800d2405a7 100644 --- a/xen/common/schedule.c +++ b/xen/common/schedule.c @@ -87,6 +87,8 @@ extern const struct scheduler *__start_schedulers_array[], *__end_schedulers_arr static struct scheduler __read_mostly ops; +static bool scheduler_active; + static struct sched_resource * sched_idle_res_pick(const struct scheduler *ops, const struct sched_unit *unit) { @@ -2241,6 +2243,13 @@ static struct sched_unit *sched_wait_rendezvous_in(struct sched_unit *prev, cpu_relax(); *lock = pcpu_schedule_lock_irq(cpu); + + if ( unlikely(!scheduler_active) ) + { + ASSERT(is_idle_unit(prev)); + atomic_set(&prev->next_task->rendezvous_out_cnt, 0); + prev->rendezvous_in_cnt = 0; + } } return prev->next_task; @@ -2589,14 +2598,32 @@ const cpumask_t *sched_get_opt_cpumask(enum sched_gran opt, unsigned int cpu) return mask; } +static void schedule_dummy(void) +{ + sched_tasklet_check_cpu(smp_processor_id()); +} + +void scheduler_disable(void) +{ + scheduler_active = false; + open_softirq(SCHEDULE_SOFTIRQ, schedule_dummy); + open_softirq(SCHED_SLAVE_SOFTIRQ, schedule_dummy); +} + +void scheduler_enable(void) +{ + open_softirq(SCHEDULE_SOFTIRQ, schedule); + open_softirq(SCHED_SLAVE_SOFTIRQ, sched_slave); + scheduler_active = true; +} + /* Initialise the data structures. */ void __init scheduler_init(void) { struct domain *idle_domain; int i; - open_softirq(SCHEDULE_SOFTIRQ, schedule); - open_softirq(SCHED_SLAVE_SOFTIRQ, sched_slave); + scheduler_enable(); for ( i = 0; i < NUM_SCHEDULERS; i++) { diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h index cc65922b88..bfd5517ac4 100644 --- a/xen/include/xen/sched.h +++ b/xen/include/xen/sched.h @@ -933,6 +933,8 @@ void restore_vcpu_affinity(struct domain *d); void vcpu_runstate_get(struct vcpu *v, struct vcpu_runstate_info *runstate); uint64_t get_cpu_idle_time(unsigned int cpu); void sched_guest_idle(void (*idle) (void), unsigned int cpu); +void scheduler_enable(void); +void scheduler_disable(void); /* * Used by idle loop to decide whether there is work to do: